Starting arrangement for internal combustion engines with fuel injection



Dec. 23. 1969 A] ARENDT ETAL 3,485,226

STARTING ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES WITH FUEL INJECTION 2 Sheets-Sheet 1 Filed May 13, 1968 FIG.7

M/VENTORS Alfred ARENDT Erwin NA'GELE Karl WOLF Jim J'M zhel'r A TI'ORNEY Dec. 23. 1969 A. ARENDT ETAL 3,485,226 STARTING ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES WITH FUEL INJECTION 2 Sheets-Sheet 2 ,Filed May 13 1968 lNVL'NTORS Alfred ARENDT Erwin NA'GELE Karl WOLF he/r ATTORNEY nited States Patent O 3,485,226 STARTING ARRANGEMENT FOR INTERNAL COM- BUSTION ENGINES WITH FUEL INJECTION Alfred Arendt, Ensingen, Erwin Nagele, Hessigheim, and Karl Wolf, Stuttgartonnenberg, Germany, assignors to Robert Bosch G.m.b.H., Stuttgart, Germany Filed May 13, 1968, Ser. No. 728,401 Claims priority, application Germany, May 19, 1967, B 92,609 Int. Cl. F02n 17/02 US. Cl. 123142.5 13 Claims ABSTRACT OF THE DISCLOSURE An arrangement for starting a cold diesel engine which comprises a glow plug serving to produce flames in the intake manifold of the engine on completion of a circuit. The glow plug then receives fuel from a separate tank by way of an auxiliary pump which is built into the tank. The latter receives leak fuel from the injection nozzles of the engine.

CROSS-REFERENCE TO RELATED APPLICATIONS The arrangement of our present invention constitutes an improvement over and a further development of arrangements disclosed in Patent No. 3,353,520 granted to Haag on Nov. 21, 1967 and in copending applications Ser. Nos. 571,899 and 571,900, filed Aug. 11, 1966 by Wolf and assigned to the same assignee.

BACKGROUND OF THE INVENTION The present invention relates to internal combustion engines in general, and more particularly to impr vements in arrangements which are utilized to facilitate starting of cold internal combustion engines. Still more particularly, the invention relates to an arrangement for starting of internal combustion engines of the type wherein fuel is injected into the cylinders.

In presently known arrangements Of this character, a glow plug is installed in the intake manifold of the engine to produce flash flames which heat the cylinders when the circuit of a heating element in the glow plug is completed. The glow plug receives fuel directly from the fuel tank of the engine or from a reservoir which is supplied with fuel by the fuel pump or supply pump, i.e., by that pump which delivers fuel to the injection pump. Reference may be had to the aforementioned Patent No. 3,353,520 to Haag. When the glow plug receives fuel directly from the main source, i.e., from the fuel tank, the output of the fuel pump must be increased accordingly so that the latter can deliver fuel to the injection pump as well as to the glow plug. The situation is aggravated if the fuel tank is remote from the glow plug, for example, in an automotive SUMMARY OF THE INVENTION It is an object of our invention to provide a novel and improved arrangement which can be utilized to facilitate or to render possible the starting of internal combustion engines with fuel injection and wherein the means for supplying fuel to the glow plug may comprise a relatively small and compact pump which may but need not be of the self-priming type.

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Another object of the invention is to provide an arrangement wherein the conduit which delivers fuel to the glow plug can be automatically and fluid tightly sealed against escape of fuel or against entry of air even if the arrangement remains idle for extended periods of time.

A further object of the invention is to provide a novel pump which can be utilized in an arrangement of the above outlined character.

An additional object of the invention is to provide an arrangement which need not receive fuel directly from the fuel tank and wherein the absence of such direct connection between the glow plug and the fuel tank reduces the likelihood of leakage and other undesirable phenomena, even when the glow plug is not used for long periods of time and even when the pressure of fuel in the source which is cOnnectable with the glow plug fluctuates within a wide range.

With the above objects in view, our invention is embodied in an internal combustion engine, particularly in a diesel engine, which comprises a first source of fuel, at least one fuel injecting element, feed lines means connecting the injecting element with the first source and containing a fuel injection pump, an intake manifold, a glow plug comprising fuel discharging nozzle means extending into the intake manifold and heating means for heating fuel in the nozzle means, an auxiliary source of fuel, auxiliary pump means operative to effect admission of fuel from the auxiliary source to the nozzle means of the glow plug, and conduit means for supplying to the auxiliary source some of the fuel which passes through the injection pump. The auxiliary source is preferably located at a point which is considerably closer to the glow plug than the first source, and the auxiliary source can return surplus fuel to the first source by way of an overflow conduit.

In accordance with a presently preferred embodiment of our invention, the auxiliary source is a tank which can receive leak fluid from one or more injecting elements of the engine.

Another feature of our invention resides in the provision of special auxiliary pump means which is built into and forms with the auxiliary source a structural unit which preferably also includes one or more valves serving to prevent escape of fuel, entry of air and/ or propagation of pressures from the manifold to the auxiliary source when the auxiliary pump means is idle.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved arrangement itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of a specific embodiment with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary diagrammatic view of a diesel engine with fuel injection which embodies the improved arrangement; and

FIG. 2 is an enlarged axial sectional View of a fuel tank and a pump in the arrangement of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The arrangement which is shown in FIG. 1 comprises torch glow plug 11 of the type disclosed in Patent No. 3,353,520 to Haag. The glow plug 11 comprises an apertured nozzle 11a which extends into the intake manifold 12 of an internal combustion engine. The nozzle 11a exchanges heat with an electric heating element 11b of the glow plug 11 so that it heats fuel which is admitted by way of a supply conduit 13. The thus heated fuel passes through the apertures of the nozzle 11a and produces flash flames on contact with air which flows in the intake manifold 12. The flames penetrate into and heat the cylinders of the engine. This facilitates starting of the engine on a cold day. One terminal of the heating element 11b is grounded and its other terminal is connected to a control switch 15 by way of a conductor 14. A monitoring lamp 16 in the conductor 14 lights up when the circuit of the heating element 11b is completed.

The glow plug 11 receives fuel indirectly from the main source (full tank) 21 of the engine. The tank 21 contains diesel oil. A first feed line 22 draws fuel from the tank 21 when the engine drives a fuel pump 23. The latter causes the fuel to flow from the feed line 22 into a second feed line 22a which contains a filter 24 and supplies fuel to an injection pump 25. Surplus fuel returns from the filter 24 to the tank 21 by way of a return line 24a. The injection pump 25 supplies fuel into feed lines 26 (only one shown) each of which is connected with an injection nozzle 27. Each of these nozzles has a first outlet 27a which discharges atomized fuel into the respective cylinder and a second outlet 27b which receives leak fuel and is connected to a collecting conduit 28. The conduits 28 discharge leak fuel into an auxiliary tank 29 which accommodates an electromagnetically operated auxiliary pump 30 and can return surplus fuel to the tank 21 by way of an overflow conduit 31. The auxiliary tank 29 is mounted on the casing of the engine at a point close to the intake manifold 12. The function of the auxiliary pump 30 is to supply fuel to the conduit 13 and hence to the nozzle 11a of the glow plug 11.

The aforementioned control switch 15 comprises a movable contact 32 which is connected to the positive pole of a battery B or another suitable source of electrical energy and which is movable between the positions a, b and c. When in the position b, the movable contact 32 engages a first fixed contact 33 which is connected to the conductor 14, Le, the circuit of the heating element 11b in the glow plug 11 is then completed. When in the position 0, the movable contact 32 engages the fixed contact 33 and also a second fixed contact 34 which is connected with the solenoid 36 of the electromagnet (FIG. 2) for the auxiliary pump 30 by a conductor 35. The circuits of the heating element 11b and solenoid 36 are open when the movable contact 32 returns to the idle position a. A further conductor 37 connects the fixed contact 34 with the electric circuit of the starter (not shown) for the diesel engine.

The auxiliary tank 29 comprises a cover or lid 41 9 (FIG. 2) having two nipples 42, 43 which are respectively connected to the conduits 28 and 31. The central portion of the cover 41 is provided with a hub 44 which extends into the interior of the auxiliary tank 29 and accommodates the aforementioned solenoid 36 and a sleeve 45 of ferrous material which surrounds the solenoid. A flexible annular diaphragm 46 forms part of the pumping member in the auxiliary pump 30; its outer marginal portion is clamped between the end face of the hub 44 and an annular shoulder 47 provided on the bottom wall of the tank 29. The inner marginal portion of the diaphragm 46 is clamped between two rings 48, 49 which are aflixed to a reciprocable plunger 50 constituting another part of the aforementioned pumping member in the pump 30. The plunger 50 is integral with the reciprocable armature 51 of the electromagnet and the ring 48 abuts against one end convolution of a helical return spring 52. The other end convolution of the return spring 52 bears against a metallic retainer 53 which is fixedly mounted in the hub 44. The upper end portion of the armature 51 actuates an interrupter switch (not shown) which serves as a means for periodically opening the circuit of the electromagnet. The interrupter switch is installed in a. switch box 54 which is secured to the tank 29 by screws 55. These crews also serve to connect the cover 41 to the main body portion of the tank 29.

The hub 44 of the cover 29 is formed with radial apertures or bores 56 which admit fuel from the compartment 29a of the tank 29 into a first pump chamber 57. The chamber 57 can be placed in communication with a second pump chamber 58 by way of channels 59 formed by registering openings or holes provided in the rings 48. 49 and diaphragm 46. The lower end of the plunger (as viewed in FIG. 2) carries an elastic disk 60 which is slipped onto a stub of the plunger and whose marginal portion 61 lies flat against the adjacent underside of the lower ring 49. The latter constitutes the seat of a suction valve in the pump 30, and the diaphragm 60 constitutes the valve member of this suction valve. A further diaphragm -62 seals the pump chamber '57 from the solenoid 36; this diaphragm 62 is of annular shape and its central portion is rigidly clamped to the plunger 50 or armature 51.

The bottom wall of the auxiliary tank 29 has an internally threaded socket 63 which receives an externally threaded nipple 64 connected with the intake end of the supply conduit 13. The lower zone of the compartment 29a accommodates a heating coil 65 which can be connected in circuit with the battery B to heat fuel in the compartment 29a and to thus reduce the viscosity of fuel on cold days. The pump chamber 58 is connected with the interior of the socket '63 by channels or passages 66 provided in a horizontal partition 67 of the tank 29. The partition 67 constitutes the seat of a pressure-responsive one-way valve whose valve member 68 consists of elastic material and is connected to the partition 67 so as to overlie the lower ends of the passages 66.

The pump chamber 58 accommodates an annular extension 69 of the pump housing whose top part constitutes the seat of a solenoid valve. The marginal portion 61 of the disk 60 constitutes the valve member of this solenoid valve and the latter also includes the armature 51 and solenoid 36. The function of the solenoid valve is to supervise the flow of fuel from the compartment 29a of the tank 29 into the conduit 13 and hence into the nozzle 11a of the glow plug 11. This solenoid valve is provided in addition to the aforementioned valves including the parts 49, 60 and 67, 68.

The operation of the arrangement shown in FIG. I is as follows:

When the movable contact 32 of the control switch 15 assumes the position a of FIG. 1, the circuit of the electric heating element 111: in the glow plug 11 is open. Also, the switch 15 then prevents energization of the solenoid 36 in the electromagnet of the auxiliary pump 30. The return spring 52 maintains the plunger 50 in the idle position which is shown in FIG. 2 and in which the disk shaped valve member 60 bears against the seats 49 and 69. This insures that the compartment 29a of the auxiliary tank 29 is tightly sealed from the supply conduit 13 and that no fuel can be admitted to the nozzle 11b of the glow plug 11 even if the auxiliary pump 30 is at a standstill for extended periods of time. Fuel in the tank 29 exerts pressure against the diaphragm 46 (in the chamber 57) and also against the diaphragm 62. The two pressures balance each other so that fluctuations in pressure of fuel in the compartment 29a of the tank 29 have no effect on the solenoid valve including the parts 60 and 69. The oneway valve 67, 68 and the suction valve 49, 60 prevent'propagation of elevated pressures (if any) from the intake manifold 12 into the tank 29 by way of the supply conduit 13. In the absence of these valves, such elevated pressures could cause fuel to return from the conduit 13 back into the compartment 29a.

When the engine is cold, the operator moves the contact 32 of the control switch 15 from the idle position a to the position b. The circuit of the heating element 11/) in the glow plug 11 is then completed and the heating element 11b exchanges heat with the nozzle 11a. In the next step, the operator moves the contact 32 to the position 0 to thereby complete the circuit of the solenoid 36 while the circuit of the heating element 11b remains completed. At the same time, the contact 32 completes the circuit of the starter (conductor 37). The pump delivers fuel from the tank 29 into. the conduit 13 and the latter admits fuel to the nozzle 11a of the glow plug 11. The nozzle 11a is heated to a temperature at which the fuel evaporates and is ignited on contact with air in the intake manifold 12 to produce flames which penetrate into and heat the cylinders of the engine. This either facilitates or renders possible starting of the engine on a cold day. The interrupter switch in the switch box 54 effects intermittent opening of the circuit for the solenoid 36 so that the pumping member 46, performs a series of pumping strokes.

When the movable contact 32 returns to the idle position a, the circuits of the starter, pump 30 and glow plug 11 are open. The spring 52 then rgturns the plunger 50 to the position shown in FIG. 2 and the disk is sealingly clamped between the seats 49 and 69.

An important advantage of the improved arrangement is that the auxiliary tank 29 can be placed very close to the glow plug 11, i.e., much closer than the main source 21 and that the auxiliary tank 29 need not receive fuel directly from such main source. In other words, the tank 29 can receive fuel from one or more components (injection nozzles 27) which are also closely adjacent to the intake manifold 12 so that the paths along which fuel flows from the nozzles 27 to the tank 29 and from the tank 29 to the nozzle 11a of the glow plug 11 are much shorter than in presently known arrangements. The tank 29 is rather small and can be readily installed in any such space which is available close to the glow plug 11 and injection nozzles 27.

Another advantage of the improved arrangement is that the auxiliary pump 30 is mounted directly in or on the tank 29. Thus, there is no need for conduits between the tank 29 and pump 30 and the latter need not be selfpriming. Additional savings in space are achieved due to the fact that the tank 29, pump 30 and the electromagnet 36, 45, 51 form a compact unitary structure which also includes the aforementioned solenoid valve having the seat 69. Such structure is especially compact if the solenoid valve and the pump 30 are mounted in the main body portion of the tank 29.

It will be noted that the solenoid 36 forms part of the elcctromagnet which actuates the plunger 50 of the pump 30 and of the solenoid valve. This results in additional savings in space, material and manufacturing cost. The solenoid valve closes automatically when the auxiliary pump 30 is idle.

The elastic disk 60 constitutes a component part of two valves, namely of the aforementioned suction and solenoid valves. This also contributes to compactness, lower cost and greater simplicity of the arrangement. In fact, the entire solenoid valve is assembled of parts which also perform other functions. Fuel in the pump chamber 57 exerts pressure against the disk 60 and thereby enhances the sealing action between this disk and the seat 69.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In an internal combustion engine, a combination comprising a first first source of fuel; at least one fuel injection element; feed line means connecting said injection element with said source; a fuel injection pump in said feed line means; an intake manifold; a glow plug comprising fuel discharging nozzle means extending into said manifold and heating means for heating fuel in said nozzle means at the will of the operator of the engine; an auxiliary source of fuel; auxiliary pump means operative to effect admission of fuel from said auxiliary source to said nozzle means; valve means provided between said auxiliary source and said nozzle means, said valve means comprising solenoid means energizable to permit flow of fuel from said auxiliary pump means to said nozzle means and means for preventing flow of fuel between said nozzle means and said pump means in either direction in response to de-energization of said solenoid means, said auxiliary pump means, said auxiliary source and said valve means forming together a structural unit; and conduit means for supplying to said auxiliary source some of the fuel which passes through said injection pump.

2. A combination as defined in claim 1, wherein said auxiliary source is nearer to said glow plug than said first source.

3. A combination as defined in claim 2, wherein said injecting element has first outlet means for discharging fuel into a cylinder of the engine and second outlet means for leak fuel, said conduit means connecting said second outlet means with said auxiliary source so that said nozzle means receives said leak fuel.

4. A combination as defined in claim 1, further comprising overfiow conduit means for returning surplus fuel from said auxiliary source to said first source.

5. A combination as defined in claim 1, wherein said auxiliary pump means and said valve means are at least partially accommodated in said auxiliary source.

6. In an internal combustion engine, a combination comprising a first source of fuel; at least one fuel injecting element; feed line means connecting said injecting element with said source; a fuel injection pump in said feed line means; an intake manifold; a glow plug comprising fuel discharging nozzle means extending into said manifold and heating means for heating fuel in said nozzle means at the will of the operator of the engine; an auxil iary source of fuel; second heating means provided in said auxiliary source to heat the fuel therein; auxiliary pump means operative to effect admission of fuel from said auxiliary source to said nozzle means; and conduit means for supplying to said auxiliary source some of the fuel which passes through said injection pump.

7. A combination as defined in claim 6, wherein said auxiliary source comprises a tank having a bottom wall and defining a fuel-receiving compartment above said bottom wall, said second heating means being located in said compartment adjacent to said bottom Wall.

8. In an internal combustion engine, a combination comprising first source of fuel; at least one fuel injecting element; feed line means connecting said inject-elements with said source; a fuel injection pump in said feed line means; an intake manifold; a glow plug comprising fuel discharge nozzle means extending into said manifold and heating means for heating fuel in said nozzle means at the will of the operator of the engine; an auxiliary source of fuel; auxiliary pump means operative to effect admission of fuel from said auxiliary source to said nozzle means and comprising a movable pumping member, elec tromagnet means including solenoid means energizable to thereby move said pumping member from a first to a second position, and resilient means for biasing said pumping member to said first position; valve means having a seat defining a portion of a passage between said auxiliary pump means and said nozzle means and a valve member biased against said seat by said resilient means and arranged to move away from said seat in response to energization of said solenoid means; and conduit means for supplying to said auxiliary source some of the fuel which passes through said injection pump.

9. A combination as defined in claim 8, further comprising a second valve seat disposed between said first mentioned valve seat and said auxiliary source and defining a second portion of said passage, said valve member being biased against both said seats in deenergized condition of said solenoid means.

10. A combination as defined in claim 9, wherein said valve member is connected to and is movable with said pumping member, said second valve seat and said valve member together constituting a suction valve of said auxiliary pump means arranged to draw fuel from said auxiliary source in response to movement of said pumping member from first position.

11. A combination as defined in claim 10, wherein said valve member is an elastic disk and wherein said second seat is secured to said pumping member, said first seat forming part of a housing in said auxiliary pump means.

12. A combination as defined in claim 11, wherein said pumping member comprises a diaphragm having a central portion connected with the armature of said elec- References Cited UNITED STATES PATENTS 2,993,487 7/ 1961 Konrad et a1. 3,353,520 11/1967 Haag. 3,379,183 4/1968 Wolf. 3,379,184 74/1968 Wolf.

LAURENCE M. GOODRIDGE, Primary Examiner US. Cl. X.R. 123-179 

